Plants with lanky, skinny stems are generally starved for light. Add more light. If plants are packed too tightly together they will stretch for the light and get tall and lanky. Reduce density and/or thin branches. Oscillating fans blowing over your plants can help somewhat in reducing stretching of branches and helps with botrytis and in promoting dense mats of trichomes. Some think the excessive air movement may promote more severe cases of powdery mildew. I fog a pesticide made plant based ingredients every night for about 5 minutes (just long enough to get a visible fog and I have it on a timer) and that keeps pm, aspergillus, and botrytis in check. In summary, have good lighting, don't let your crop get too dense, move air through it (enough to get a little wiggle action from leaves and stems) and prevent diseases by spraying proactively.